ioctl()函数获取本机IP、MAC

#include <sys/ioctl.h>
int ioctl(int d, int request, ...);

/* Socket configuration controls. */
#define SIOCGIFADDR 0x8915    /* get PA address */
#define SIOCSIFADDR 0x8916    /* set PA address */
#define SIOCGIFHWADDR 0x8927  /* Get hardware address */

struct ifreq，Interface request structure，在头文件<net/if.h>

#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/ioctl.h>
#include <net/if.h>

int main()
{
int sock;
int res;
struct ifreq ifr;

sock = socket(AF_INET, SOCK_STREAM, 0);
strcpy(ifr.ifr_name, "eth0");
res = ioctl(sock, SIOCGIFADDR, &ifr);

printf("IP: %s\n",inet_ntoa(((struct sockaddr_in*)&ifr.ifr_addr)->sin_addr));

strcpy(ifr.ifr_name, "eth0");
res = ioctl(sock, SIOCGIFHWADDR, &ifr);

int i;
char mac[32];
for(i = 0; i < 6; ++i)
{
sprintf(mac + 3*i, "%02x:", (unsigned char)ifr.ifr_hwaddr.sa_data[i]);
}
printf("MAC: %s\n",mac);

return 0;
}